Personal cleansing products have traditionally been marketed in a variety of forms such as bar soaps, creams, lotions, and gels. These cleansing formulations have attempted to satisfy a number of criteria to be acceptable to consumers. In order to be acceptable to consumers, a product must exhibit good cleansing properties, must exhibit good lathering characteristics, must be mild to the skin and preferably should provide a moisturizing benefit to the skin. Ideal personal cleansers should gently cleanse the skin or hair, cause little or no irritation, and not leave the skin or hair overly dry after frequent use.
These traditional forms of personal cleansing products have included two types of formulations, oil free cleansers and oil and water emulsions. The oil free cleansers utilize water based surfactants, fatty acid soaps, synthetic isethionates and the like to remove dirt and oil from the skin. However, many of these surfactants, especially fatty acid soaps, have been found to be irritating to the skin. Milder components and water based humectants are used in order to minimize the skin drying and irritation negatives. The oil and water emulsions utilize insoluble skin conditioning oils along with the water based cleansing systems. The products are formulated to balance the cleansing benefits of the water phase and the conditioning benefits of the oils, which are deposited on the skin. However, it is known that the emulsification of oils in water cleaners negatively impacts the lathering and cleansing properties of the products.
Recently, cosmetics manufacturers have introduced silicone based make-ups, especially lipsticks, which resist smear and rub-off. However, as products are designed to resist removal, they by their nature are more difficult to wash off. The traditional oil free cleansers and oil and water emulsion cleansers have difficulty removing these new products, without being irritating to the skin. A need need clearly exists to develop a method for cleansing the face and specifically a method for removing make-up from the skin.
It has been surprisingly found in the present invention that personal cleansing products can be formulated with properties designed to soften and remove the silicone in these new make-up products. It has been found that solutions of lathering surfactant and water having a pH of less than 8.3 and having an interfacial tension of less than 3.5 provide improved ability to remove silicone based compounds from the skin without increasing skin irritation. The methods of the present invention are highly efficacious for cleansing the skin of the face, especially for removing silicone based compounds from the face. Without being limited by theory, it is believed that the lower than typical interfacial tension better softens and breaks up the lipid and silicone base of the make-up compound. The lower than typical pH reduces irritation over soaps products. This combination provides the improved make-up removal benefit of the methods of the present invention.
The present invention relates to methods of cleaning lipid and silicone based compounds from a solid substrate.
The present invention also relates to methods of cleaning the skin of the face and methods for removing make-up from the face using compositions in which the pH and interfacial tension have been adjusted to remove silicone based compounds from the skin. The methods provide improved cleansing and make-up removal over traditional cleansing methods of cleaning the face.
This and other objects of this invention will become apparent in light of the following disclosure.